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19-Soft-A4 Real-Time Systems: May 2013

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

  1. Question 1 What a Real-Time System Is, With Three Worked Examples
  2. Question 2 Maximum Decision-Logic Delay Before Tank Spill-Over
  3. Question 3 FCFS vs. EDF Scheduling of Four Real-Time Tasks
  4. Question 4 Finite-State Traffic-Light Controller for a Signalized Intersection
  5. Question 5 State-Transition Design of a Household Washing-Machine Controller
  6. Question 6 Networked (Distributed) Control Loop — Protocol, Delay Effects and Stability Margin

Start with Question 1 →

National Exams — May 2013 — 04-Soft-A4 Real-Time Systems. Three-hour, closed-book exam (Casio or Sharp approved calculators only). Format: six questions of equal value (20% each); any five constitute a complete paper and only the first five as they appear in the answer book are marked. All six are solved below for completeness. Where a doubt exists as to interpretation, the candidate is expected to state assumptions — engineering assumptions used below are flagged in check callouts.

Reference texts: Jane W. S. Liu, Real-Time Systems (Prentice Hall, 2000) — task models, timing requirements, FCFS and EDF scheduling; Giorgio C. Buttazzo, Hard Real-Time Computing Systems: Predictable Scheduling Algorithms and Applications (Springer, 3rd ed.) — preemptive dynamic-priority scheduling and the optimality of EDF; Hermann Kopetz, Real-Time Systems: Design Principles for Distributed Embedded Applications (Springer, 2nd ed.) — distributed real-time control, network-induced delay and time-triggered protocols; Katsuhiko Ogata, Modern Control Engineering (Pearson, 5th ed.) — frequency-domain stability, phase margin and delay margin; Ian Sommerville, Software Engineering (Pearson, 10th ed.) — general software-engineering process context.